Credit: Will & Grace: Chris Haston

Memorable ”Will & Grace” guest stars: Jennifer Lopez

J. Lo wasn’t above poking fun at her own much-married status in the season 6 finale, when Karen asks her to perform at her own abortive wedding. Lopez returned for the ending of that cliffhanger, the season 7 premiere, in which Karen tries to get J. Lo backup dancer Jack to help her pitch the pop star a song she’s written called ”FYI: I Hurt Too.” No wonder Lopez fires Jack, though she makes it up to him by getting him the Janet Jackson gig. See, she’s not a diva.